The present invention relates to a centrifugal elutriator rotor, i.e. a centrifuge rotor for continuous separation of different types of specimen particles carried by a liquid buffer that is pumped through the rotor. The basic principles of a centrifugal elutriator rotor can be summarized as follows. The liquid buffer (such as water) carrying the specimen particles, is pumped from an outer end of a separation chamber, disposed within a rotating rotor, and pass through this chamber along a path directed substantially radially inward with respect to the axis of rotation of the rotor, and hence to the inner end of the separation chamber. Separation of particles having respectively different physical properties, e.g. different size, is thereby accomplished based on the relationship between the respective values of centrifugal force and liquid flow force acting upon the specimen particles. These forces will be determined at any instant during the elutriation process, for each particle, by the distance of the particle from the axis of rotation of the rotor, the particle size, and the rate of flow of the liquid buffer carrying the particle at that instant. An example of such a centrifugal elutriator rotor is described in U.S. Pat. No. 4,350,283. However such a prior art type of centrifugal elutriator rotor presents the following problems. Firstly, separation is carried out within a short tubular elutriation cell which is attached in the body of the rotor. Thus, the volume of the rotor which is actually utilized for separation purposes is very small, so that the efficiency of separation is low, i.e. the amount of material which can be separated by a single centrifuging operation, is small. In addition, the elutriation cell must be removed from the interior of the rotor, then once more attached therein, e.g. by screwing and unscrewing an end cap which retains the cell within the rotor, each time a centrifuging operation is repeated. Thus, operation is inconvenient and time-consuming.
A further disadvantage of this prior art rotor, which also applies to various other types of prior art centrifugal elutriator rotor, is that it is necessary for the operator to employ a stroboflash type of light source in order to observe the progress of separation of specimen particles while the rotor is rotating. This is necessitated by the fact that the elutriation process is performed only within a segment of the rotor.